Designing a Model via Grounded Theory to Reduce Agricultural Work Injury among Orchardists in Ilam Province.

The present study aimed to design a model to reduce agricultural work injury among orchardists in Ilam Province, Iran. This was a qualitative research study that used grounded theory to analyze data. The study included 25 specialists, managers, and experts of horticulture in Ilam Province who were selected through purposive sampling.

Dynamical properties of the hydration shell of fully deuterated myoglobin.

Freeze-dried perdeuterated sperm whale myoglobin was kept in a water-saturated atmosphere in order to obtain a hydration degree of 335 H(2)O molecules per one myoglobin molecule. Incoherent neutron scattering was performed at the neutron spectrometer TOFTOF at the FRM II in an angular range of q from 0.6 to 1.

On the feasibility of nanocrystal imaging using intense and ultrashort X-ray pulses.

Structural studies of biological macromolecules are severely limited by radiation damage. Traditional crystallography curbs the effects of damage by spreading damage over many copies of the molecule of interest in the crystal. X-ray lasers offer an additional opportunity for limiting damage by out-running damage processes with ultrashort and very intense X-ray pulses.

Protein dynamics of a beta-sheet protein.

Rhodnius prolixus Nitrophorin 4 (abbreviated NP4) is an almost pure beta-sheet heme protein. Its dynamics is investigated by X-ray structure determination at eight different temperatures from 122 to 304 K and by means of Mössbauer spectroscopy. A comparison of this beta-sheet protein with the pure alpha-helical protein myoglobin (abbreviated Mbmet) is performed.

Cooperative Iron(II) spin crossover complexes with N4O2 coordination sphere.

Two new spin crossover complexes [FeL(py)(2)] (1) and [FeL(DMAP)(2)] (2) with L being a tetradentate N(2)O(2)(2-) coordinating Schiff-base-like ligand [([3,3']-[1,2-phenylenebis(iminomethylidyne)]bis(2,4-pentanedionato)(2-)-N,N',O(2),O(2)'], py = pyridine and DMAP = p-dimethylaminopyridine have been investigated using temperature-dependent susceptibility and thermogravimetric and photomagnetic measurements as well as Mössbauer spectroscopy and X-ray structure analysis. Both complexes show a cooperative spin transition with an approximately 9 K wide thermal hysteresis loop in the case of 2 (T(1/2) upward arrow = 183 K and T(1/2) downward arrow = 174 K) and an approximately 2 K wide thermal hysteresis loop in the case of the pyridine diadduct 1 (T(1/2) upward arrow = 191 K and T(1/2) downward arrow = 189 K). The spin transition was additionally followed by different temperature-scanning calorimetry and Mössbauer spectroscopy for 2, and a good agreement for the transition temperatures obtained with the different methods was found.

A physical picture of protein dynamics and conformational changes.

A physical model is reviewed which explains different aspects of protein dynamics consistently. At low temperatures, the molecules are frozen in conformational substates. Their average energy is 3/2RT.

The configuration of the Cu(2+) binding region in full-length human prion protein compared with the isolated octapeptide.

The cellular prion protein (PrP(C)) is a copper binding protein. The molecular features of the Cu(2+) binding sites have been investigated and characterized by spectroscopic experiments on PrP(C)-derived peptides and the correctly folded human full-length PrP(C) (hPrP-[23-231]). These experiments allowed us to distinguish two different configurations of copper binding.

The configuration of the Cu2+ binding region in full-length human prion protein.

The cellular prion protein (PrP(C)) is a Cu(2+) binding protein connected to the outer cell membrane. The molecular features of the Cu(2+) binding sites have been investigated and characterized by spectroscopic experiments on PrP(C)-derived peptides and the recombinant human full-length PrP(C )(hPrP-[23-231]). The hPrP-[23-231] was loaded with (63)Cu under slightly acidic (pH 6.

Seeded growth of asymmetric binary nanocrystals made of a semiconductor TiO2 rodlike section and a magnetic gamma-Fe2O3 spherical domain.

Asymmetric binary nanocrystals (BNCs), comprising one c-axis elongated anatase TiO2 section and one gamma-Fe2O3 spherical domain attached together, are synthesized by heterogeneous nucleation of iron oxide onto the longitudinal facets of TiO2 nanorods in a ternary surfactant mixture. The topologically controlled composition of the BNCs is ascertained by a combination of powder X-ray diffraction, Raman and Mössbauer spectroscopy, high-angle annular dark-field imaging, and high-resolution transmission electron microscopy lattice fringe mapping, while their size-dependent magnetic behavior is demonstrated by ac susceptibility measurements. The heteroepitaxial growth proceeds through a mechanism never observed before for colloidal nanoheterostructures: the two domains share a restricted and locally curved junction region, which accommodates efficiently the interfacial strain and retards the formation of misfit dislocations.

Colloidal synthesis and characterization of tetrapod-shaped magnetic nanocrystals.

Tetrapod-shaped maghemite nanocrystals are synthesized by manipulating the decomposition of iron pentacarbonyl in a ternary surfactant mixture under mild thermal conditions. Adjustment of the reaction parameters allows for the systematic tuning of both the width and the length of the tetrapod arms, which grow preferentially along the 111 easy axis direction. Such degree of control leads to modulation of the magnetic behavior of the nanocrystals, which evolves systematically as their surface magnetization phase and shape anisotropy are progressively increased.

Targeting cancer cells: magnetic nanoparticles as drug carriers.

Magnetic drug targeting employing nanoparticles as carriers is a promising cancer treatment avoiding side effects of conventional chemotherapy. We used iron oxide nanoparticles covered by starch derivatives with phosphate groups which bound mitoxantrone as chemotherapeutikum. In this letter we show that a strong magnetic field gradient at the tumour location accumulates the nanoparticles.

Reduced and oxidized cytochrome c4 exhibit differences in dynamics.

The temperature-dependent dynamics of the fully reduced and fully oxidized forms of Pseudomonas stutzeri cytochrome c4 have been studied by Mössbauer spectroscopy. Prior to the dynamic analysis, an efficient labelling strategy has been developed for the expression of highly enriched (57)Fe recombinant cytochrome c4. Subsequently, the protein has been purified to apparent homogeneity.

Spectral broadening of the Soret band in myoglobin: an interpretation by the full spectrum of low-frequency modes from a normal modes analysis.

In this work the temperature dependence of the Soret band line shape in carbon-monoxy myoglobin is re-analyzed by using both the full correlator approach in the time domain and the frequency domain approach. The new analyses exploit the full density of vibrational states of carbon-monoxy myoglobin available from normal modes analysis, and avoid the artificial division of the entire set of vibrational modes coupled to the Soret transition into "high-frequency" and "low-frequency" subsets; the frequency domain analysis, however, makes use of the so-called short-times approximation, while the time domain one avoids it. Time domain and frequency domain analyses give very similar results, thus supporting the applicability of the short-times approximation to the analysis of hemeprotein spectra; in particular, they clearly indicate the presence of spectral heterogeneity in the Soret band of carbon-monoxy myoglobin.

Ligand migration pathway and protein dynamics in myoglobin: a time-resolved crystallographic study on L29W MbCO.

By using time-resolved x-ray crystallography at room temperature, structural relaxations and ligand migration were examined in myoglobin (Mb) mutant L29W from nanoseconds to seconds after photodissociation of carbon monoxide (CO) from the heme iron by nanosecond laser pulses. The data were analyzed in terms of transient kinetics by fitting trial functions to integrated difference electron density values obtained from select structural moieties, thus allowing a quantitative description of the processes involved. The observed relaxations are linked to other investigations on protein dynamics.

Ligand migration and protein fluctuations in myoglobin mutant L29W.

We have determined eight X-ray structures of myoglobin mutant L29W at various experimental conditions. In addition, infrared spectroscopic experiments are presented, which are discussed in the light of the X-ray structures. Two distinct conformations of the CO-ligated protein were identified, giving rise to two stretching bands of heme-bound CO.

[Magnetic Drug Targeting--a new approach in locoregional tumor therapy with chemotherapeutic agents. Experimental animal studies].

Background: Advanced squamous cell carcinomas of the head and neck region were often treated with combined radio-chemotherapy. Radiotherapy allows a focused treatment of the tumor, and healthy tissue can be protected from radiation. Chemotherapy, however, is mostly given systemically and the unwanted negative side effects also develop in many other organs.

A new method to determine the structure of the metal environment in metalloproteins: investigation of the prion protein octapeptide repeat Cu(2+) complex.

Since high-intensity synchrotron radiation is available, "extended X-ray absorption fine structure" spectroscopy (EXAFS) is used for detailed structural analysis of metal ion environments in proteins. However, the information acquired is often insufficient to obtain an unambiguous picture. ENDOR spectroscopy allows the determination of hydrogen positions around a metal ion.

Micellar environments induce structuring of the N-terminal tail of the prion protein.

In the physiological form, the prion protein is a glycoprotein tethered to the cell surface via a C-terminal glycosylphosphatidylinositol anchor, consisting of a largely alpha-helical globular C-terminal domain and an unstructured N-terminal portion. This unstructured part of the protein contains four successive octapeptide repeats, which were shown to bind up to four Cu(2+) ions in a cooperative manner. To mimic the location of the protein on the cell membrane and to analyze possible structuring effects of the lipid/water interface, the conformational preferences of a single octapeptide repeat and its tetrameric form, as well of the fragment 92-113, proposed as an additional copper binding site, were comparatively analyzed in aqueous and dodecylphosphocholine micellar solution as a membrane mimetic.

Hydration structures in proteins and neutron diffraction experiment on dissimilatory sul te reductase D (DsrD).

Neutron crystallography can provide a substantial amount of information about the hydration of proteins. The hydration patterns of three proteins, whose structures have been solved at 1.5 or 1.

Proteins in action: the physics of structural fluctuations and conformational changes.

Structural dynamics is essential for the biological function of proteins. Results from new experimental techniques should be compared with those from previous experiments in order to obtain a consistent picture of the physics of intramolecular fluctuations and conformational changes. The high intensity and time structure of synchrotron radiation have made possible time-resolved X-ray structure analysis and the determination of phonon density spectra through the Mössbauer effect.

Magnetic drug targeting--biodistribution of the magnetic carrier and the chemotherapeutic agent mitoxantrone after locoregional cancer treatment.

Magnetic Drug Targeting means the specific delivery of chemotherapeutic agents to their desired targets, e.g. tumors, by using magnetic nanoparticles (ferrofluids) bound to these agents and an external magnetic field which is focused on the tumor.

Hydrogen atoms in proteins: positions and dynamics.

Hydrogen atoms constitute about half of the atoms in proteins. Thus they contribute to the complex energy landscape of proteins [Frauenfelder, H., Sligar, S.

A water network within a protein: temperature-dependent water ligation in H64V-metmyoglobin and relaxation to deoxymyoglobin.

The sperm whale myoglobin mutant H64V, where the distal histidine is mutated to valine, is known to be five coordinated in the ferric state at room temperature and physiological pH. A change of the ligation in this H64V-Mbmet has been observed by optical absorption spectroscopy as a function of temperature from 20 K to 300 K. Above the dynamical transition at about 180 K one observes the temperature-dependent equilibrium between five- and six-ligated heme.